Remington Steele's offices are at least ten stories up with few buildings nearby. In order to fire a bullet through the office window the killer would need access to a space at sufficient level.
In Dancer, Prancer, Donner and Steele (1985), it's revealed the owner of the building that houses the Steele agency lives nearby, in a different building close enough and high enough to give him an unobstructed view of it just by looking out his window.
In Dancer, Prancer, Donner and Steele (1985), it's revealed the owner of the building that houses the Steele agency lives nearby, in a different building close enough and high enough to give him an unobstructed view of it just by looking out his window.